In a fluidic oscillator the oscillation frequency of the fluid jet is directly dependent on the velocity of the fluid in the jet stream. If the differential pressure across the oscillator is held constant, then the density of the fluid is directly proportional to a constant divided by the square of the oscillation frequency. Such oscillators are disclosed in the above-referenced patents.
When employed as density sensors these oscillators are combined with pressure regulators (such as the regulator 42 illustrated in FIG. 2 of the '127 patent) to provide the constant differential pressure that is required. However, the pressure regulators are relatively massive, accounting for over ninety percent of the weight of the density meter. This creates problems in applications such as aircraft, for example, where weight and volume considerations may determine the choice made from among various density metering schemes.
An objective of this invention is to provide a process for electrofluidic liquid density measurement that accommodates the condition of varying differential pressure across the oscillator.
A further objective is to provide relatively light-weight and low-volume apparatus adapted for use with the above-mentioned process.